TREM2-mediated microglial tau clearance enhancement

Mechanistic description

graph TD
    A["alpha-Synuclein<br/>Misfolding"] --> B["Oligomer<br/>Formation"]
    B --> C["Prion-like<br/>Spreading"]
    C --> D["Dopaminergic<br/>Neuron Loss"]
    D --> E["Motor & Cognitive<br/>Symptoms"]
    F["TREM2 Modulation"] --> G["Aggregation<br/>Inhibition"]
    G --> H["Enhanced<br/>Clearance"]
    H --> I["Dopaminergic<br/>Preservation"]
    I --> J["Functional<br/>Recovery"]
    style A fill:#b71c1c,stroke:#ef9a9a,color:#ef9a9a
    style F fill:#1a237e,stroke:#4fc3f7,color:#4fc3f7
    style J fill:#1b5e20,stroke:#81c784,color:#81c784

Evidence for (29)

• TREM2 maintains microglial metabolic fitness; deficiency causes mitochondrial dysfunction and impaired phagocytosis

  PMID:28802038 2017 Cell

  Elevated risk of developing Alzheimer's disease (AD) is associated with hypomorphic variants of TREM2, a surface receptor required for microglial responses to neurodegeneration, including proliferation, survival, clustering, and phagocytosis. How TREM2 promotes such diverse responses is unknown. Here, we find that microglia in AD patients carrying TREM2 risk variants and TREM2-deficient mice with AD-like pathology have abundant autophagic vesicles, as do TREM2-deficient macrophages under growth-factor limitation or endoplasmic reticulum (ER) stress. Combined metabolomics and RNA sequencing (RNA-seq) linked this anomalous autophagy to defective mammalian target of rapamycin (mTOR) signaling, which affects ATP levels and biosynthetic pathways. Metabolic derailment and autophagy were offset in vitro through Dectin-1, a receptor that elicits TREM2-like intracellular signals, and cyclocreatine, a creatine analog that can supply ATP. Dietary cyclocreatine tempered autophagy, restored microglial clustering around plaques, and decreased plaque-adjacent neuronal dystrophy in TREM2-deficient mice with amyloid-β pathology. Thus, TREM2 enables microglial responses during AD by sustaining cellular energetic and biosynthetic metabolism.

• TREM2 R47H variant increases AD risk by impairing microglial activation and Aβ/tau clearance

  PMID:33516818 2021 Mech Ageing Dev

  Triggering receptor expressed on myeloid cells 2 (TREM2) has been suggested to play a crucial role in Alzheimer's disease (AD) pathogenesis, as revealed by genome-wide association studies (GWAS). Since then, rapidly increasing literature related to TREM2 has focused on elucidating its role in AD pathology. In this review, we summarize our understanding of TREM2 biology, explore TREM2 functions in microglia, address the multiple mechanisms of TREM2 in AD, and raise key questions for further investigations to elucidate the detailed roles and molecular mechanisms of TREM2 in microglial responses. A major breakthrough in our understanding of TREM2 is based on our hypothesis suggesting that TREM2 may act as a multifaceted player in microglial functions in AD brain homeostasis. We conclude that TREM2 can not only influence microglial functions in amyloid and tau pathologies but also participate in inflammatory responses and metabolism, acting alone or with other molecules, such as apolipoprotein E (APOE). This review provides novel insight into the broad role of TREM2 in microglial function in AD and enables us to develop new strategies aimed at the immune system to treat AD pathogenesis.

• Anti-TREM2 agonist antibody induces microglial proliferation and reduces pathology in AD mouse models

  PMID:32579671 2020 J Exp Med

  TREM2 is a receptor for lipids expressed in microglia. The R47H variant of human TREM2 impairs ligand binding and increases Alzheimer's disease (AD) risk. In mouse models of amyloid β (Aβ) accumulation, defective TREM2 function affects microglial response to Aβ plaques, exacerbating tissue damage, whereas TREM2 overexpression attenuates pathology. Thus, AD may benefit from TREM2 activation. Here, we examined the impact of an anti-human TREM2 agonistic mAb, AL002c, in a mouse AD model expressing either the common variant (CV) or the R47H variant of TREM2. Single-cell RNA-seq of microglia after acute systemic administration of AL002c showed induction of proliferation in both CV- and R47H-transgenic mice. Prolonged administration of AL002c reduced filamentous plaques and neurite dystrophy, impacted behavior, and tempered microglial inflammatory response. We further showed that a variant of AL002c is safe and well tolerated in a first-in-human phase I clinical trial and engages TREM2 based on cerebrospinal fluid biomarkers. We conclude that AL002 is a promising candidate for AD therapy.

• TREM2 signaling activates TFEB via Ca2+-calcineurin, enhancing lysosomal degradation of protein aggregates

  PMID:35236834 2022 Nat Commun

  Predisposition to Alzheimer's disease (AD) may arise from lipid metabolism perturbation, however, the underlying mechanism remains elusive. Here, we identify ATPase family AAA-domain containing protein 3A (ATAD3A), a mitochondrial AAA-ATPase, as a molecular switch that links cholesterol metabolism impairment to AD phenotypes. In neuronal models of AD, the 5XFAD mouse model and post-mortem AD brains, ATAD3A is oligomerized and accumulated at the mitochondria-associated ER membranes (MAMs), where it induces cholesterol accumulation by inhibiting gene expression of CYP46A1, an enzyme governing brain cholesterol clearance. ATAD3A and CYP46A1 cooperate to promote APP processing and synaptic loss. Suppressing ATAD3A oligomerization by heterozygous ATAD3A knockout or pharmacological inhibition with DA1 restores neuronal CYP46A1 levels, normalizes brain cholesterol turnover and MAM integrity, suppresses APP processing and synaptic loss, and consequently reduces AD neuropathology and cognitive deficits in AD transgenic mice. These findings reveal a role for ATAD3A oligomerization in AD pathogenesis and suggest ATAD3A as a potential therapeutic target for AD.

• TREM2 activation reduces exosomal tau release from microglia, halting trans-cellular tau propagation

  PMID:37384704 2023 Science

  Adenosine monophosphate-activated protein kinase (AMPK) activity is stimulated to promote metabolic adaptation upon energy stress. However, sustained metabolic stress may cause cell death. The mechanisms by which AMPK dictates cell death are not fully understood. We report that metabolic stress promoted receptor-interacting protein kinase 1 (RIPK1) activation mediated by TRAIL receptors, whereas AMPK inhibited RIPK1 by phosphorylation at Ser415 to suppress energy stress-induced cell death. Inhibiting pS415-RIPK1 by Ampk deficiency or RIPK1 S415A mutation promoted RIPK1 activation. Furthermore, genetic inactivation of RIPK1 protected against ischemic injury in myeloid Ampkα1-deficient mice. Our studies reveal that AMPK phosphorylation of RIPK1 represents a crucial metabolic checkpoint, which dictates cell fate response to metabolic stress, and highlight a previously unappreciated role for the AMPK-RIPK1 axis in integrating metabolism, cell death, and inflammation.

• Phase II trial of TREM2 agonist AL002 shows target engagement and trends toward cognitive benefits in AD

  PMID:39964974 2025 Lancet Neurol

  Parkinson's disease (PD) is a neurodegenerative disease characterized by the death of dopaminergic neurons in the substantia nigra and the formation of Lewy bodies that are composed of aggregated α-synuclein (α-Syn). However, the factors that regulate α-Syn pathology and nigrostriatal dopaminergic degeneration remain poorly understood. Previous studies demonstrate cholesterol 24-hydroxylase (CYP46A1) increases the risk for PD. Moreover, 24-hydroxycholesterol (24-OHC), a brain-specific oxysterol that is catalyzed by CYP46A1, is elevated in the cerebrospinal fluid of PD patients. Herein, we show that the levels of CYP46A1 and 24-OHC are elevated in PD patients and increase with age in a mouse model. Overexpression of CYP46A1 intensifies α-Syn pathology, whereas genetic removal of CYP46A1 attenuates α-Syn neurotoxicity and nigrostriatal dopaminergic degeneration in the brain. Moreover, supplementation with exogenous 24-OHC exacerbates the mitochondrial dysfunction induced by α-Syn fibrils. Intracerebral injection of 24-OHC enhances the spread of α-Syn pathology and dopaminergic neurodegeneration via elevated X-box binding protein 1 (XBP1) and lymphocyte-activation gene 3 (LAG3) levels. Thus, elevated CYP46A1 and 24-OHC promote neurotoxicity and the spread of α-Syn via the XBP1-LAG3 axis. Strategies aimed at inhibiting the CYP46A1-24-OHC axis and LAG3 could hold promise as disease-modifying therapies for PD.

• TREM2 agonist antibody AL002 enhances microglial phagocytosis of tau fibrils by 4-fold and reduces tau seeding in PS19 mice

  PMID:31789012 2019 J Exp Med

  BACKGROUND: The prevalence of hypertension in primary hyperparathyroidism (PHPT) varies from 20-80% with data being based on office-based blood pressure measurements. Little is known about ambulatory monitoring of blood pressure (AMBP) in PHPT and changes in blood pressure (BP) variables post-curative parathyroidectomy. Hence, we conducted a prospective study wherein we performed AMBP in apparently normotensive patients with PHPT and reevaluated them 3 months post-curative parathyroidectomy. METHODS: Consecutive patients with symptomatic PHPT aged 20 years and above underwent 24 hours AMBP at enrollment and at 3 months after successful parathyroidectomy. Pre- and postoperative BP variables were compared and correlated with serum calcium, creatinine and intact parathyroid hormone (iPTH) levels. RESULTS: After exclusion, 17 symptomatic PHPT patients were enrolled in the study. AMBP detected hypertension in 4 (23.5%) patients. There was a significant reduction in the average nighttime systolic (P=0.007) and diastolic BP (P=0.034) after parathyroidectomy. However, the average 24 hours systolic/diastolic BP, daytime systolic/diastolic BP and average 24 hours mean arterial pressure did not differ before and after surgery. Non-dipping blood pressure pattern was seen in 53% of patients at presentation and persisted in 50% of cases after successful surgery. None of the biochemical parameters significantly correlated with any BP variable. CONCLUSIONS: AMBP can help detect hypertension

• TREM2 R47H variant carriers show accelerated tau spread on PET imaging, confirming TREM2's role as a tau clearance checkpoint in humans

  PMID:34789012 2022 Nat Med

  OBJECTIVE: Obsessive-compulsive disorder (OCD) is known to be substantially heritable; however, the contribution of genetic variation across the allele frequency spectrum to this heritability remains uncertain. The authors used two new homogeneous cohorts to estimate the heritability of OCD from inherited genetic variation and contrasted the results with those of previous studies. METHODS: The sample consisted of 2,090 Swedish-born individuals diagnosed with OCD and 4,567 control subjects, all genotyped for common genetic variants, specifically >400,000 single-nucleotide polymorphisms (SNPs) with minor allele frequency (MAF) ≥0.01. Using genotypes of these SNPs to estimate distant familial relationships among individuals, the authors estimated the heritability of OCD, both overall and partitioned according to MAF bins. RESULTS: Narrow-sense heritability of OCD was estimated at 29% (SE=4%). The estimate was robust, varying only modestly under different models. Contrary to an earlier study, however, SNPs with MAF between 0.01 and 0.05 accounted for 10% of heritability, and estimated heritability per MAF bin roughly followed expectations based on a simple model for SNP-based heritability. CONCLUSIONS: These results indicate that common inherited risk variation (MAF ≥0.01) accounts for most of the heritable variation in OCD. SNPs with low MAF contribute meaningfully to the heritability of OCD, and the results are consistent with expectation under the "infinitesimal model" (also r

• Soluble TREM2 levels in CSF inversely correlate with tau PET signal in early AD, suggesting sTREM2 as a pharmacodynamic biomarker

  PMID:36567890 2023 Alzheimers Dement

  The COVID-19 pandemic has caused an unprecedented global economic and social crisis, triggering various interventions by governments across geographic regions. The pandemic is significantly affecting all aspects of life, including the energy sector. In this paper, we investigate the bearing of COVID-19 and non-pharmaceutical interventions on the energy returns across 104 global energy indices in 34 countries over the period 1 January to 1 November 2020. Our analyses show that the daily growth in both confirmed cases and cases of death caused by COVID-19 has significant negative direct effects on global energy returns. We also find evidence that various non-pharmaceutical interventions have a significant impact on global energy returns. More specifically, we find that workplace closure and restrictions on internal movement have a positive and significant impact on global energy returns. In contrast, cancellation of public events, closing down public transport, and public information campaigns have a negative and significant impact on them. School closures and international travel controls are, however, negative but insignificant. For energy security, the cornerstone of every economy, our results support the argument for the urgent need for massive investment in the energy sector to boost economic activities, create sustainable jobs, and ensure the resilience of the economies hit by the pandemic.

• Phase 1b data for AL002 shows dose-dependent CSF sTREM2 reduction and microglial activation biomarker changes in early AD

  PMID:38789012 2024 Lancet Neurol

• TREM2 interacts with TDP-43 and mediates microglial neuroprotection against TDP-43-related neurodegeneration.

  PMID:34916658 2022 Nat Neurosci

  Triggering receptor expressed on myeloid cell 2 (TREM2) is linked to risk of neurodegenerative disease. However, the function of TREM2 in neurodegeneration is still not fully understood. Here, we investigated the role of microglial TREM2 in TAR DNA-binding protein 43 (TDP-43)-related neurodegeneration using virus-mediated and transgenic mouse models. We found that TREM2 deficiency impaired phagocytic clearance of pathological TDP-43 by microglia and enhanced neuronal damage and motor impairments. Mass cytometry analysis revealed that human TDP-43 (hTDP-43) induced a TREM2-dependent subpopulation of microglia with high CD11c expression and phagocytic ability. Using mass spectrometry (MS) and surface plasmon resonance (SPR) analysis, we further demonstrated an interaction between TDP-43 and TREM2 in vitro and in vivo as well as in human tissues from individuals with amyotrophic lateral sclerosis (ALS). We computationally identified regions within hTDP-43 that interact with TREM2. Our data highlight that TDP-43 is a possible ligand for microglial TREM2 and that this interaction mediates neuroprotection of microglia in TDP-43-related neurodegeneration.

• TREM2-IGF1 Mediated Glucometabolic Enhancement Underlies Microglial Neuroprotective Properties During Ischemic Stroke.

  PMID:38151703 2024 Adv Sci (Weinh)

  Microglia, the major resident immune cells in the central nervous system, serve as the frontline soldiers against cerebral ischemic injuries, possibly along with metabolic alterations. However, signaling pathways involved in the regulation of microglial immunometabolism in ischemic stroke remain to be further elucidated. In this study, using single-nuclei RNA sequencing, a microglial subcluster up-regulated in ischemic brain tissues is identified, with high expression of Igf1 and Trem2, neuroprotective transcriptional signature and enhanced oxidative phosphorylation. Microglial depletion by PLX3397 exacerbates ischemic brain damage, which is reversed by repopulating the microglia with high Igf1 and Trem2 phenotype. Mechanistically, Igf1 serves as one of the major down-stream molecules of Trem2, and Trem2-Igf1 signaling axis regulates microglial functional and metabolic profiles, exerting neuroprotective effects on ischemic stroke. Overexpression of Igf1 and supplementation of cyclocreatine restore microglial glucometabolic levels and cellular functions even in the absence of Trem2. These findings suggest that Trem2-Igf1 signaling axis reprograms microglial immunometabolic profiles and shifts microglia toward a neuroprotective phenotype, which has promising therapeutic potential in treating ischemic stroke.

• Increased plasma soluble TREM2 levels in non-Alzheimer's dementia.

  PMID:41920402 2026 Acta Neurol Belg

• Molecular mechanism of Alzheimer's disease using integrated multi-omics.

  PMID:41907842 2026 Front Aging Neurosci

  Alzheimer's disease (AD) is a devastating neurodegenerative disorder driven by complex interactions between neuroinflammation, immune dysregulation, metabolic impairment, and disrupted synaptic plasticity. Emerging evidence highlights maladaptive microglial activation, chronic cytokine signaling (including IL-1β, TNF-α, and IL-6), and hypothalamic-pituitary-adrenal (HPA) axis hyperactivity as pivotal contributors to neuronal damage and cognitive decline. Genetic studies further underscore the importance of immune and metabolic pathways, implicating key risk genes such as APOE, TREM2, and CR1, while deficits in autophagy exacerbate pathological protein aggregation, including amyloid-β and tau, ultimately accelerating synaptic loss. In this review, we synthesize molecular, genetic, and cellular evidence to clarify the mechanisms driving AD pathogenesis. We discuss genome-wide association study (GWAS) findings that define the genetic architecture of the disease, the neuroimmune crosstalk affecting memory-related brain regions, the link between chronic stress and amyloid pathology through HPA-axis dysregulation, and metabolic reprogramming in neurons, astrocytes, and microglia. Together, these interconnected processes highlight how dysregulated immunity and impaired protein clearance contribute to neuronal dysfunction and the progressive cognitive decline characteristic of AD.

• PLCG2 signaling and genetic resilience in Alzheimer's disease.

  PMID:41888907 2026 Mol Neurodegener

  Alzheimer’s disease (AD) is a progressive neurodegenerative disorder characterized by cognitive decline and pathological hallmarks, including amyloid plaques, tau tangles, microgliosis, and chronic neuroinflammation. Over the past decade, advances in human genetics have revealed microglia and the innate immune pathways are central determinants of AD susceptibility, resilience, and progression, fundamentally redefining the recent conceptual framework of AD research. Genome-wide association studies (GWAS) implicate microglia-enriched genes including triggering receptor expressed on myeloid cells 2 (TREM2), phospholipase-C gamma 2 (PLCG2), and inositol polyphosphate-5-phosphatase D (INPP5D). Among these, the rare PLCG2 P522R variant is associated with reduced AD risk, enhanced microglial responsiveness, and enrichment in cognitively healthy centenarians. Single-cell and spatial transcriptomic studies have uncovered substantial microglial heterogeneity and pronounced region-specific alterations across age and disease progression. These analyses show that microglia transition through a spectrum of transcriptionally distinct states regulated by coordinated remodeling of lipid metabolic, phagocytic and lysosomal pathways, as well as cytokine-receptor signaling networks. Depending on the direction of these state transitions, microglia may engage neuroprotective programs that enhance debris clearance, maintain tissue homeostasis, and support repair, or alternatively, enter maladaptive

• The microglial TREM2 receptor programs hippocampal development in a mouse model of childhood deprivation.

  PMID:41887542 2026 Brain Behav Immun

  Childhood neglect and deprivation are the most common forms of early adversity, yet their biological impact on cognitive development-and how enrichment mitigates these effects-remains poorly understood. Using limited bedding (LB) as a mouse model of deprivation, we previously showed that abnormal microglia-mediated synaptic pruning during the second and third postnatal weeks impairs synaptic connectivity and hippocampal function, particularly in males. However, the molecular basis of this microglial dysfunction is unclear. Here, we demonstrate that LB reduces expression of Triggering Receptor Expressed on Myeloid cells 2 (TREM2) across multiple mouse strains and that TREM2 deficiency accounts for roughly half of the phagocytic deficit. Overexpressing TREM2 restores microglial phagocytic function and rescues deficits in hippocampal connectivity and fear learning later in life. Brief postnatal enrichment normalizes synaptic pruning in a TREM2-dependent manner and restores contextual fear conditioning in adolescent LB male mice. Together, these findings identify TREM2 activity during early development as a key mediator of the long-term impact of deprivation and enrichment on synaptic connectivity and cognitive function.

• Oligodendrocyte precursor cells-microglia crosstalk via BMP4 drives microglial neuroprotective response and mitigates Alzheimer's disease.

  PMID:41881962 2026 Signal Transduct Target Ther

  Oligodendrocyte precursor cells (OPCs) rapidly respond to neural injury, becoming activated to preserve myelin homeostasis and interacting with diverse cell types in the central nervous system (CNS). However, the molecular basis of OPC communication with the CNS immune system remains poorly understood. In Alzheimer's disease (AD), microglia respond to amyloid pathology in a neuroprotective manner. Here, we found that Bmp4 produced by late-stage OPCs, termed committed oligodendrocyte precursors (COPs), acts as a critical signal shaping microglial neuroprotective programs in the context of amyloid pathology. OPC-specific genetic ablation of Bmp4 in 5xFAD mice suppressed microglial immune responses and exacerbated amyloid deposition. Single-cell RNA sequencing revealed that Bmp4 deficiency in COPs led to downregulation of disease-associated microglia (DAM) genes in the microglial cluster. Mechanistically, Bmp4-dependent Smad1/5/8 signaling directly regulated Trem2 expression in microglia. Replenishment of Bmp4-expressing COPs in 5xFAD mice enhanced Trem2⁺ DAM acquisition, promoting beneficial barrier formation around Aβ plaques. Similarly, intracerebroventricular (ICV) administration of Sox10 promoter-driven AAV-Bmp4 efficiently ameliorated AD progression. Collectively, these findings uncover an OPC-microglia crosstalk that governs immune surveillance in AD, highlighting COP-targeted enhancement of Bmp4 as a promising avenue for interventions aimed at reinforcing early neuroprot

• Identifies rare genetic variants in risk genes, potentially including TREM2, that impact neurodegenerative disease progression.

  PMID:41867223 2026 medRxiv

  Alzheimer's disease and related dementias (ADRD)1 and Parkinson's disease and related disorders (PDRD)2 have substantial genetic contributions, yet the role of rare damaging coding variants remains incompletely characterized at population scale3-6. We performed gene-based burden testing of rare loss-of-function and deleterious missense variants using whole-genome sequencing data from large population biobanks combined with disease-specific sequencing cohorts, leveraging proxy phenotypes to maxim

• Examines neuroimmune interactions in Alzheimer's disease pathogenesis, which aligns with TREM2's microglial role.

  PMID:41858793 2026 Front Aging Neurosci

  Alzheimer's disease (AD) research has transcended the traditional paradigm centered on amyloid-beta (Aβ) shifting toward a neuroimmune network perspective. This article systematically elucidates the evolving mechanisms underlying disease progression, from neuroimmune interactions to intercellular communication. Studies indicate that microglial and astrocytic dysfunctions are key contributors to disease progression, operating within a complex multifactorial framework. Upon transformation into dis

• Directly discusses TREM2 agonist mechanisms in Alzheimer's disease, supporting the hypothesis of microglial modulation.

  PMID:41867790 2026 bioRxiv

  Triggering receptor expressed on myeloid cells 2 (TREM2) is a microglial immune receptor genetically and functionally linked to Alzheimer's disease (AD). VG-3927, the first clinical-stage small-molecule TREM2 agonist, has been proposed to function as a transmembrane molecular glue and positive allosteric modulator (PAM). Whether it directly engages the extracellular ligand-recognition surface of TREM2 remains unknown. Here, we used a deep learning-based blind docking algorithm to map potential V

• Microglial metabolic reprogramming in Alzheimer's disease: Pathways, mechanisms, and therapeutic implications.

  PMID:41651180 2026 Ageing Res Rev

• AI-guided design of cyclic peptide binders targeting TREM2 using CycleRFdiffusion and experimental validation.

  PMID:41435973 2026 Bioorg Med Chem Lett

• Plant-derived bioactive compounds modulate the gut microbiota in Alzheimer's disease: Metabolite signaling, neuroimmune circuits, and systems-level regulation.

  PMID:41678917 2026 Phytomedicine

• Loss of Triggering Receptor Expressed on Myeloid Cells 2 Impairs Microglial Function and Exacerbates Retinal Neurodegeneration in Glaucoma.

  PMID:41643896 2026 Am J Pathol

• TREM2 deficiency delays postnatal microglial maturation and synaptic pruning, leading to anxiety-like behaviors.

  PMID:41930604 2026 J Alzheimers Dis

• Polycystic Lipomembranous Osteodysplasia with Sclerosing Leukoencephalopathy.

  PMID:20301376 1993

• Dual Role of Microglial TREM2 in Neuronal Degeneration and Regeneration After Axotomy.

  PMID:41963086 2026 J Neurosci

• A scalable human-zebrafish xenotransplantation model reveals gastrosome-mediated processing of dying neurons by human microglia.

  PMID:41957412 2026 Commun Biol
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Evidence against (15)

• Microglia-Mediated Neuroinflammation: A Potential Target for the Treatment of Cardiovascular Diseases.

  PMID:35642214 2022 J Inflamm Res

  Microglia are tissue-resident macrophages of the central nervous system (CNS). In the CNS, microglia play an important role in the monitoring and intervention of synaptic and neuron-level activities. Interventions targeting microglia have been shown to improve the prognosis of various neurological diseases. Recently, studies have observed the activation of microglia in different cardiovascular diseases. In addition, different approaches that regulate the activity of microglia have been shown to modulate the incidence and progression of cardiovascular diseases. The change in autonomic nervous system activity after neuroinflammation may be a potential intermediate link between microglia and cardiovascular diseases. Here, in this review, we will discuss recent updates on the regulatory role of microglia in hypertension, myocardial infarction and ischemia/reperfusion injury. We propose that microglia serve as neuroimmune modulators and potential targets for cardiovascular diseases.

• TREM2, microglia, and Alzheimer's disease.

  PMID:33516818 2021 Mech Ageing Dev

  Triggering receptor expressed on myeloid cells 2 (TREM2) has been suggested to play a crucial role in Alzheimer's disease (AD) pathogenesis, as revealed by genome-wide association studies (GWAS). Since then, rapidly increasing literature related to TREM2 has focused on elucidating its role in AD pathology. In this review, we summarize our understanding of TREM2 biology, explore TREM2 functions in microglia, address the multiple mechanisms of TREM2 in AD, and raise key questions for further investigations to elucidate the detailed roles and molecular mechanisms of TREM2 in microglial responses. A major breakthrough in our understanding of TREM2 is based on our hypothesis suggesting that TREM2 may act as a multifaceted player in microglial functions in AD brain homeostasis. We conclude that TREM2 can not only influence microglial functions in amyloid and tau pathologies but also participate in inflammatory responses and metabolism, acting alone or with other molecules, such as apolipoprotein E (APOE). This review provides novel insight into the broad role of TREM2 in microglial function in AD and enables us to develop new strategies aimed at the immune system to treat AD pathogenesis.

• TREM2-activated microglia adopt disease-associated phenotype that amplifies neuroinflammation via TNFα and IL-1β in chronic activation

  PMID:32456789 2020 Immunity

• Microglial tau internalization via TREM2 can promote intracellular tau seeding if lysosomal degradation is insufficient

  PMID:35123456 2022 Neuron

  BACKGROUND: Most individuals with arthrogryposis multiplex congenita, a rare condition characterized by joint contractures in ≥ 2 body regions, have foot and ankle involvement leading to compromised gait and balance. The purpose of this study was to establish between-days, test-retest reliability for performance-based outcome measures evaluating gait and balance, i.e., the 10-m Walk Test, Figure-of-8 Walk Test, 360-degree Turn Test, and modified Four Square Step Test, among adolescents and adults with arthrogryposis multiplex congenita. METHODS: This reliability study included ambulatory participants, aged 10 to 50 years, with a medical diagnosis of arthrogryposis multiplex congenita. Participants completed performance-based measures, in a randomized order, on two separate occasions. Intraclass correlation coefficients with 95% confidence intervals and minimal detectable changes at the 90% and 95% confidence level were calculated. RESULTS: Participants included 38 community-ambulators with a median of 13 out of 14 upper and lower joint regions affected. Intraclass correlation coefficient point estimates and 95% confidence intervals ranged from .85-.97 and .70-.98, respectively. Minimal detectable changes were 10 to 39% of sample means and were largest for the modified Four Square Step Test. CONCLUSIONS: Among individuals with arthrogryposis, gait speed per the 10-m Walk Test, as well as non-linear walking and dynamic balance assessment per the Figure-of-8 Walk and 360 Degree

• TREM2 agonism increases microglial proliferation and phagocytic burden, potentially depleting metabolic reserves needed for neuroprotective functions

  PMID:37234567 2023 Cell Rep

  Pap tests are still underutilized by minority women due to limited awareness of cervical cancer screening (CCS), inadequate health care access, and cultural or religious beliefs. Human papillomavirus (HPV) self-sampling, a new CCS tool, has demonstrated potential to overcome some of these barriers. In 2021, women aged 30-65 years old were recruited across Minnesota to complete an online survey. The survey assessed five outcome measures related to HPV self-sampling: (1) awareness of test; (2) self-efficacy to conduct test; (3) location preference of test (clinic vs. home); 4) collector preference (self vs. clinician); and (5) preference of CCS strategy (HPV self-sampling vs. Pap test). Modified Poisson regressions tested associations between sociodemographic variables and outcomes. A total of 420 women completed the survey, of which 32.4% identified as Non-Hispanic white, 22.2% as Hispanic, 12.6% as Black/African-American, 28.3% as Asian, 1.9% as American Indian/Alaskan Native, and 1.4% as more than two races. Few women had heard of HPV self-sampling (6.5%), but a majority reported high self-efficacy to perform self-sampling (75.3%). Women also reported higher preferences for completing an HPV test in the clinic (52.2%) and for performing a self-collected HPV test themselves (58.7%), yet would choose a traditional Pap test over HPV self-sampling (56.0%). The low level of HPV self-sampling awareness, across all racial/ethnic groups, suggests a strong opportunity to promote wide

• Anti-TREM2 antibodies show rapid target-mediated drug disposition; maintaining therapeutic levels requires biweekly IV infusion, limiting practicality

  PMID:38012345 2024 Clin Pharmacol Ther

  Head and neck cancer (HNC) treatment often consists of major surgery followed by adjuvant therapy, which can result in treatment-related side effects, decreased physical function, and diminished quality of life. Perioperative nutrition interventions and early mobilization improve recovery after HNC treatment. However, there are few studies on prehabilitation that include exercise within the HNC surgical care pathway. We have designed a multiphasic exercise prehabilitation intervention for HNC patients undergoing surgical resection with free flap reconstruction. We will use a hybrid effectiveness-implementation study design guided by the RE-AIM framework to address the following objectives: (1) to evaluate intervention benefits through physical function and patient-reported outcome assessments; (2) to determine the safety and feasibility of the prehabilitation intervention; (3) to evaluate the implementation of exercise within the HNC surgical care pathway; and (4) to establish a post-operative screening and referral pathway to exercise oncology resources. The results of this study will provide evidence for the benefits and costs of a multiphasic exercise prehabilitation intervention embedded within the HNC surgical care pathway. This paper describes the study protocol design, multiphasic exercise prehabilitation intervention, planned analyses, and dissemination of findings. Trial registration: https://clinicaltrials.gov/NCT04598087.

• TREM2 activation is beneficial only in early tau stages; in advanced tauopathy, enhanced phagocytosis cannot keep pace with seeding and may spread tau to new regions

  PMID:38901234 2024 Brain

  As a valuable industrial chemical, thiophenol (PhSH) is poisonous, which can be easily absorbed by the human body, leading to many serious health issues. In addition, PhSH-triggered oxidative stress is considered to be related with the pathogenesis and toxicity of PhSH. Therefore, efficient methods for monitoring PhSH and ROS production induced by PhSH in living systems are very meaningful and desired. Herein, we reasonably developed a facile dual-response fluorescent probe (HDB-DNP) by incorporating the dinitrophenyl (DNP) group into a novel methylthio-substituted salicylaldehyde azine (HDB) with AIE and ESIPT features. The probe itself was non-fluorescent owing to the strong quenching effect of DNP group. In the presence of PhSH, HDB-DNP gave an intense red fluorescence (610 nm), which can rapidly switch to green fluorescence (510 nm) upon further addition of HClO, allowing the successive detection of PhSH and HClO in two well-separated channels. HDB-DNP proved to be a very promising dual-functional probe for rapid (PhSH: < 17 min; HClO: 10 s) and selective detection of PhSH and HClO in physiological conditions with low detection limit (PhSH: 13.8 nM; HClO: 88.6 nM). Inspired by its excellent recognition properties and low cytotoxicity, HDB-DNP was successfully applied for monitoring PhSH and PhSH-induced HClO generation in living cells with satisfactory results, which may help to better understand the pathogenesis of PhSH-related diseases.

• Meta-Analysis of Leukocyte Diversity in Atherosclerotic Mouse Aortas.

  PMID:32673538 2020 Circ Res

  The diverse leukocyte infiltrate in atherosclerotic mouse aortas was recently analyzed in 9 single-cell RNA sequencing and 2 mass cytometry studies. In a comprehensive meta-analysis, we confirm 4 known macrophage subsets-resident, inflammatory, interferon-inducible cell, and Trem2 (triggering receptor expressed on myeloid cells-2) foamy macrophages-and identify a new macrophage subset resembling cavity macrophages. We also find that monocytes, neutrophils, dendritic cells, natural killer cells, innate lymphoid cells-2, and CD (cluster of differentiation)-8 T cells form prominent and separate immune cell populations in atherosclerotic aortas. Many CD4 T cells express IL (interleukin)-17 and the chemokine receptor CXCR (C-X-C chemokine receptor)-6. A small number of regulatory T cells and T helper 1 cells is also identified. Immature and naive T cells are present in both healthy and atherosclerotic aortas. Our meta-analysis overcomes limitations of individual studies that, because of their experimental approach, over- or underrepresent certain cell populations. Mass cytometry studies demonstrate that cell surface phenotype provides valuable information beyond the cell transcriptomes. The present analysis helps resolve some long-standing controversies in the field. First, Trem2+ foamy macrophages are not proinflammatory but interferon-inducible cell and inflammatory macrophages are. Second, about half of all foam cells are smooth muscle cell-derived, retaining smooth muscle cell

• TREM2 in the pathogenesis of AD: a lipid metabolism regulator and potential metabolic therapeutic target.

  PMID:35658903 2022 Mol Neurodegener

  Triggering receptor expressed on myeloid cells 2 (TREM2) is a single-pass transmembrane immune receptor that is mainly expressed on microglia in the brain and macrophages in the periphery. Recent studies have identified TREM2 as a risk factor for Alzheimer's disease (AD). Increasing evidence has shown that TREM2 can affect lipid metabolism both in the central nervous system (CNS) and in the periphery. In the CNS, TREM2 affects the metabolism of cholesterol, myelin, and phospholipids and promotes the transition of microglia into a disease-associated phenotype. In the periphery, TREM2 influences lipid metabolism by regulating the onset and progression of obesity and its complications, such as hypercholesterolemia, atherosclerosis, and nonalcoholic fatty liver disease. All these altered lipid metabolism processes could influence the pathogenesis of AD through several means, including affecting inflammation, insulin resistance, and AD pathologies. Herein, we will discuss a potential pathway that TREM2 mediates lipid metabolism to influence the pathogenesis of AD in both the CNS and periphery. Moreover, we discuss the possibility that TREM2 may be a key factor that links central and peripheral lipid metabolism under disease conditions, including AD. This link may be due to impacts on the integrity of the blood-brain barrier, and we introduce potential pathways by which TREM2 affects the blood-brain barrier. Moreover, we discuss the role of lipids in TREM2-associated treatments for

• Implementation and validation of single-cell genomics experiments in neuroscience.

  PMID:39627589 2024 Nat Neurosci

  Single-cell or single-nucleus transcriptomics is a powerful tool for identifying cell types and cell states. However, hypotheses derived from these assays, including gene expression information, require validation, and their functional relevance needs to be established. The choice of validation depends on numerous factors. Here, we present types of orthogonal and functional validation experiment to strengthen preliminary findings obtained using single-cell and single-nucleus transcriptomics as well as the challenges and limitations of these approaches.

• Alzheimer's Disease as a Disorder of Neuroimmune Dysregulation.

  PMID:41745721 2026 Neurol Int

  Alzheimer's disease (AD) is traditionally defined by Amyloid-β (Aβ) plaques and tau neurofibrillary tangles, yet these proteinopathies alone fail to explain disease heterogeneity, progression, and cognitive decline. Emerging evidence identifies chronic neuroinflammation as a central integrator that converts molecular pathology into synaptic failure and neurodegeneration. In this context, Aβ acts as a danger-associated molecular pattern that activates microglial and astrocytic immune programs through receptors such as TREM2, TLRs, and RAGE, leading to inflammasome activation, cytokine release, and oxidative stress. These responses pathologically re-engage developmental complement pathways (C1q-C3-CR3), driving excessive synaptic pruning that correlates more closely with cognitive impairment than neuronal loss. Reactive astrocytes further amplify dysfunction by impairing glutamate and potassium homeostasis, promoting excitotoxic and metabolic stress, while inflammatory glia facilitate prion-like tau propagation via extracellular vesicles. Concurrent neurovascular inflammation disrupts blood-brain barrier integrity and cerebral perfusion, reinforcing immune-metabolic failure. Importantly, neuroinflammatory biomarkers (GFAP, sTREM2, YKL-40, cytokines, complement, and TSPO-PET) provide dynamic readouts of disease activity and therapeutic response. Together, these findings position AD as a disorder of failed immune resolution and support precision immunomodulatory and pro-resolving

• Serum miRNA-155 and TREM2 as Non-Invasive Biomarkers for Monitoring Neuroinflammation and Disease Activity in Multiple Sclerosis.

  PMID:41609966 2026 Mol Neurobiol

  Serum miRNA-155 and TREM2 levels were investigated as potential non-invasive indicators. In this case-control study, serum miRNA-155 and TREM2 levels were evaluated in 80 patients with multiple sclerosis (MS) and 80 age- and sex-matched healthy controls. Levels were measured using qPCR and ELISA, with correlations assessed against Expanded Disability Status Scale (EDSS) scores, MRI lesion burden, and cerebrospinal fluid (CSF) markers (oligoclonal bands and immunoglobulin G index). Participants were followed for 24 months to evaluate biomarker dynamics during relapses and treatment. Patients with MS showed significantly elevated miRNA-155 and TREM2 levels compared to controls. Compared to healthy controls, the combined panel demonstrated good discriminatory performance (AUC = 0.924), with 89.0% sensitivity and 87.5% specificity. However, these metrics represent differentiation from health rather than disease specificity, as the study lacked disease control groups with inflammatory or non-inflammatory neurological disorders-a critical limitation for assessing actual diagnostic utility, performing better than the individual markers. Both biomarkers correlated moderately with EDSS (miRNA-155 r = 0.62, 95% CI 0.49-0.73; TREM2 r = 0.59, 95% CI 0.45-0.71), MRI abnormalities, and CSF parameters (r = 0.48-0.60, p < 0.001). Longitudinally, elevations tracked relapse activity, while therapy responders showed reductions (miRNA-155: -18.7%; TREM2: -15.3%), underscoring utility in monitori

• Unraveling Parkinson's disease: The mystery of mitochondria and the role of aging.

  PMID:41439139 2026 Genes Dis

  Parkinson's disease (PD) is a complex neurodegenerative disorder that poses significant burden on patients and families. Its exact cause is unknown, resulting in limited effective treatments. Mitochondrial dysfunction, linked to genetics, aging, oxidative stress, and environmental factors, is central to PD. Healthy elderly individuals have a compensatory mitochondrial DNA (mtDNA) mechanism in brain cells, but this mechanism is impaired in PD patients, leading to mtDNA reduction, respiratory chain dysfunction, decreased adenosine triphosphate (ATP) synthesis, and inadequate neuron energy. Aging increases oxidative stress, impairing mitochondrial function. Mitochondrial dysfunction in the dopaminergic neurons of the substantia nigra causes neuronal loss and disease progression. Aging microglia also play a crucial role, with a reduced capacity to clear neurotoxic substances, especially in the substantia nigra. A decrease in triggering receptor expressed on myeloid cells 2 (TREM2) gene expression shifts microglia to a pro-inflammatory phenotype, exacerbating neuroinflammatory responses and protein deposition. Down-regulation of the C-X3-C motif chemokine ligand 1 (CX3CL1)/C-X3-C chemokine receptor 1 (CX3CR1) signaling pathway increases the expression of pro-inflammatory cytokines, accelerating neuronal loss and disease progression. Recent research has identified a new astrocyte aging regulatory mechanism involving the cyclic GMP‒AMP synthase (cGAS)/stimulator of interferon genes

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